What’s Vulnerable › Vulnerabilities
CVE-2018-21259
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2020-06-19 · updated 2026-06-17
- Weakness: CWE-20
Description
An issue was discovered in Mattermost Server before 4.10.1, 4.9.4, and 4.8.2. It allows attackers to cause a denial of service (application hang) via a malformed link in a channel.
Affected products
- Mattermost: before 4.8.2; from 4.9.0 before 4.9.4; from 4.10.0 before 4.10.1 — fixed in 4.10.1, 4.8.2, 4.9.4
How to fix
Upgrade to a fixed version: Mattermost 4.10.1, 4.8.2, 4.9.4. Check the vendor advisory for mitigations.
References
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